<template>
  <div class="article-page">
    <nav class="my-nav van-hairline--bottom">
      <!-- 3. 动态class添加高亮 -->
      <!-- 4. 点击事件修改sorter -->
      <a :class="{ active: sorter === 'weight_desc'}" href="javascript:;" @click="sorter = 'weight_desc'">推荐</a>

      <a :class="{ active: sorter === null }" href="javascript:;" @click="sorter = null">最新</a>

      <div class="logo"><img src="@/assets/logo.png" alt=""></div>

    </nav>

    <van-list @load="onLoadMore" v-model="isLoading" :finished="isFinished" finished-text="没有更多了">

      <ArticleItem v-for="item in list" :key="item.id" :item="item" @click="$router.push('/article/' + item.id)" />
    </van-list>

  </div>

</template>

<script>
import ArticleItem from '@/components/ArticleItem.vue'
import { getArticlesAPI } from '@/api/article'
export default {
  name: 'article-page',
  components: {
    ArticleItem
  },
  data () {
    return {
      isLoading: false,
      list: [],
      current: 1,
      pageTotal: 999,
      isFinished: false,
      sorter: 'weight_desc' // 1.weight_desc或者是null
    }
  },
  methods: {

    async loadData () {
      // 6. 加锁
      this.isLoading = true
      const res = await getArticlesAPI({
        current: this.current, sorter: this.sorter // 2. 传递sorter
      })
      this.list.push(...res.data.rows)
      this.isLoading = false
      this.current++
      this.pageTotal = res.data.pageTotal

      if (this.current > this.pageTotal) {
        this.isFinished = true
      }
    },
    onLoadMore () {
      this.loadData()
    }
  },
  watch: {
    // 5.监听数据的变化，发起请求
    sorter () {
      this.list = []
      this.current = 1
      this.isFinished = false
      // 7.判断是否正在请求数据，没有的话，再发起请求
      if (!this.isLoading) {
        this.loadData()
      }
    }
  }
}
</script>

<style lang="less" scoped>
.article-page {
  margin-bottom: 50px;
  margin-top: 44px;

  .my-nav {
    height: 44px;
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    z-index: 999;
    background: #fff;
    display: flex;
    align-items: center;

    >a {
      color: #999;
      font-size: 14px;
      line-height: 44px;
      margin-left: 20px;
      position: relative;
      transition: all 0.3s;

      &::after {
        content: '';
        position: absolute;
        left: 50%;
        transform: translateX(-50%);
        bottom: 0;
        width: 0;
        height: 2px;
        background: #222;
        transition: all 0.3s;
      }

      &.active {
        color: #222;

        &::after {
          width: 14px;
        }
      }
    }

    .logo {
      flex: 1;
      display: flex;
      justify-content: flex-end;

      >img {
        width: 64px;
        height: 28px;
        display: block;
        margin-right: 10px;
      }
    }
  }
}

</style>
